ItemCollapsing プロパティ (DataMenuClientEvents)

// The client event 'ItemCollapsing' takes two parameters sender and e
// sender  is the object which is raising the event
// e is the DataMenuItemCancelEventArgs
function WebDataMenu1_ItemCollapsing(sender, e) {

    //Gets the DataMenuItem object that is collapsing
    var Item = e.getItem();

    //Gets the text of the collapsing item
    var ItemText = Item.get_text();

  if (!confirm("Are you sure you want hide child items under the item '"+ItemText+"'?"))
   //Cancels the ItemCollapsing event
   e.set_cancel(true);

}